Shark's Fin Reef, Similan Islands - Thailand Dive Sites

A dramatic block of rock rising out of the sand, Shark’s Fin Reef is one of the Similan Islands’ most exciting sites

Just Hatched, Shark's Fin Reef
Just Hatched – Shark’s Fin Reef, February 2022 © chris@divehappy.com

Shark’s Fin Reef is one of the Similan Islands dive sites that isn’t visited regularly by Similan liveaboards.

Fan and yellow snapper, Shark’s Fin Reef, February 2024 © chris@divehappy.com

In part that’s because it’s quite exposed to currents, and also because it’s at the southern end of the Similans by island number 3 where there are few other dive sites located.

Pook and Boots with school of bluestreak fusilier, Shark’s Fin Reef, February 2024 © chris@divehappy.com

As such, I’ve only dived Shark’s Fin Reef a handful of times but every time it’s been an awesome dive. The visibility each time I’ve dived it over a couple of seasons has been spectacular, 30 metres or so, letting you see the whole dive site stretched out below you as you descend.

Descending onto Shark’s Fin Reef, February 2022 © chris@divehappy.com

It’s a pretty dramatic looking site – a long, rectangular lozenge of rocks nearly a kilometre long that rises out of the surrounding white sand, which looks a little like a shark’s fin, hence the site’s name.

Yellowback fusiliers over the rocks, Shark’s Fin Reef, February 2024 © chris@divehappy.com

Once actually amongst the rocks, the size and scale of them feels like diving on some mysterious ruin. The rocks are shaped into different kinds of plateaus at different depths and there are a lot of fissures and cracks to explore.

Diver with big rocks, Shark’s Fin Reef, February 2024 © chris@divehappy.com

The bottom of the main rock area is around 28 meters and there are scattered deeper rocks off the main reef at 30 metres and going on down to 40 metres. The rock conveniently tops out at 5 metres, making it perfect for safety stops.

Pook and black sun coral with anthias, Shark’s Fin Reef, February 2024 © chris@divehappy.com

Because it’s out on its own unattached to an island, the reef can get some strong currents coming through but there’s plenty of places to move out of it and divers can move from one side to the other relatively easily.

Dark-banded fusiliers around the rocks, Shark’s Fin Reef, February 2024 © chris@divehappy.com

The currents bring a lot of fish skittering across the rocks in and out of the blue, surgeon fish, fusiliers and unicorn fish being most often sited. Napoleon wrasse also sometimes make an appearance. It’s also worth keeping a look out for the big Jenkins stingrays on the sand and the smaller, more common blue spotted rays.

Yellow snapper and reef wall, Shark’s Fin Reef, February 2024 © chris@divehappy.com

Big schools of yellow snapper are often spotted at Shark’s Fin Reef as on many other Similan dive sites – they’re always a welcome site and usually don’t mind divers too much.

Descending onto Shark’s Fin Reef, February 2022 © chris@divehappy.com

All photos taken during Similan diving seasons 2021-2022, 2022-2023 and 2023-2024. The Similan dive season runs from October to May each year. The Similan Marine National Park is closed from mid May to mid October each year, so don’t plan a liveaboard trip then!